JP2003212270A - Container for seeing through contents - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a container for seeing through the contents which is made of a polylactic acid polymer film, a paper, and a laminated material decomposing substantially in the natural environment, and of which the alignment polylactic acid film constituting a contents transparency-giving part does not lose its transparency even if it is exposed to a high temperature atmosphere in a film sticking process, so that it is possible to visibly and clearly confirm the contents. <P>SOLUTION: The alignment polylactic acid film has a surface orientation ratio ΔP of 3.0×10-<SP>-3</SP>or more. Also, according to the above film, the difference (ΔHm-ΔHc) between a crystal melting heat ΔHm generated upon increasing the temperature of the film and the heat of crystallization ΔHc generated due to crystallization during the temperature increase is 20 J/g or more, and the calculation of ä(ΔHm-ΔHc)/ΔHm} is 0.75 or more. The paper has a window formed by punching through part of it. Thus, the alignment polylactic acid film and the paper is laminated to form the container for seeing through the contents. Particularly, the alignment polylactic acid film is made as a copolymer, of which the ratio between L-lactic acid and D-lactic acid is within a range of 100:0 to 94:6, or 0:100 to 6:94. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a container for seeing through contents, which is manufactured by using a laminate material composed of a polylactic acid type polymer film and paper and decomposing in a natural environment.

[0002]

2. Description of the Related Art Paper is widely used as a packaging material. Paper is an excellent material from the viewpoint of environmental protection because it can be easily incinerated after use and decomposes even if it is left in a natural environment. However, since paper has low water resistance, oil and fat resistance, tear strength, etc., and also has insufficient gas barrier properties and moisture resistance, coated paper is used depending on the application. In order to further improve the performance, it may be used in combination with a plastic material such as polyethylene, polypropylene or polyvinyl chloride.

However, since the plastic material generally remains without being decomposed in the natural environment, the composite material often does not have a natural disintegrating property. It is also difficult to separate the paper and plastic materials for processing.

On the other hand, a so-called biodegradable plastic, which can be decomposed even when left in a natural environment, has been attracting attention in recent years as a plastic material. Among biodegradable plastics, it has been desired to put into practical use a polylactic acid-based film capable of producing a thin film, and particularly capable of compensating for the above-mentioned drawbacks of paper.

Therefore, JP-A-4-334448 discloses a biodegradable composite material in which the surface of a substrate containing vegetable fibers is coated with polylactic acid or a derivative thereof, and JP-A-4-33448.
No. 336246 discloses a thermoplastic decomposable polymer containing polylactic acid or a copolymer of lactic acid and oxycarboxylic acid as main components, and degradable laminated paper made of paper, and further discloses in JP-A-5-38784, polylactic acid or lactic acid. A degradable laminate composition comprising a thermoplastic degradable polymer containing a copolymer of oxycarboxylic acid as a main component and a regenerated cellulose film is disclosed.

[0006]

However, in the above-mentioned biodegradable composite material, degradable laminated paper and degradable laminated composition, when a substrate or paper containing vegetable fiber is laminated with a polylactic acid film. In some cases, the polylactic acid film may be broken due to its brittleness, and if the polylactic acid film is left at a high temperature after being bonded, the polylactic acid film is liable to change in appearance such as devitrification. Moreover, when the obtained laminate material is bent, whitening and cracks are likely to occur at the folds. Furthermore, even if it polishes, sufficient gloss cannot be obtained.

That is, although the techniques disclosed in the above-mentioned respective publications compensate for the defects of paper, they pose a new problem as a composite material.

The present invention solves the above-mentioned problems, and after use / disposal, paper and polylactic acid are used so that hydrolysis proceeds naturally in the soil or water to leave the original shape in the soil to be a harmless decomposed product. A degradable laminated container package with a window for seeing through the contents using a degradable laminated material composed of a polymer film and partially punching out a paper of the material to provide a window. Is provided.

[0009]

SUMMARY OF THE INVENTION The gist of the present invention is that the degree of plane orientation ΔP is 3.0 × 10 ⁻³ or more, and the heat of crystal fusion ΔHm when the film is heated and the crystal during heating. Difference (ΔHm-ΔH) from the heat of crystallization ΔHc generated by crystallization
c) is 20 J / g or more and {(ΔHm-ΔHc) / ΔH
an oriented polylactic acid-based film having m} of 0.75 or more,
It is a container for seeing through contents, which is obtained by laminating a piece of paper having a window partially formed by punching. In the oriented polylactic acid-based film, the ratio of L-lactic acid and D-lactic acid is 100: 0 to 94 :.
It is preferably a copolymer within the range of 6 or within the range of 0: 100 to 6:94.

The present invention will be described in detail below. The oriented polylactic acid-based film used in the degradable laminate material of the present invention contains polylactic acid or a copolymer of lactic acid and another hydroxycarboxylic acid as a main component, and other polymers within a range that does not impair the effects of the present invention. Materials may be mixed. Further, for the purpose of adjusting the molding processability and film physical properties, a plasticizer, a lubricant,
It is also possible to add additives such as inorganic fillers and ultraviolet absorbers, and modifiers.

Examples of lactic acid include L-lactic acid and D-lactic acid, and examples of hydroxycarboxylic acid include glycolic acid and 3-
Examples thereof include hydroxybutyric acid, 4-hydroxybutyric acid, 3-hydroxyvaleric acid, 4-hydroxyvaleric acid and 6-hydroxycaproic acid.

As the polymerization method, any known method such as a condensation polymerization method and a ring-opening polymerization method can be adopted, and a small amount of a chain extender such as a diisocyanate compound or an epoxy resin is used for the purpose of increasing the molecular weight. A compound, an acid anhydride, etc. may be used. The weight average molecular weight of the polymer is preferably from 50,000 to 1,000,000. When the weight average molecular weight is below this range, practical physical properties are hardly exhibited, and when it is above this range, the melt viscosity becomes too high and the moldability becomes poor.

Film forming conditions for an unstretched sheet will be described. The polylactic acid polymer is sufficiently dried to remove water, and then melted by an extruder. Since the melting temperature changes depending on the composition, it is preferable to appropriately select the melting temperature.
In practice, a temperature range of 140 ° C to 250 ° C is usually chosen.

The polymer melt-formed into a sheet is preferably brought into contact with a rotating casting drum (cooling drum) to be rapidly cooled. The temperature of the casting drum is preferably 50 ° C. or lower. If it is higher than this, the polymer sticks to the casting drum and cannot be removed. Further, since crystallization is promoted and spherulites develop and it becomes impossible to stretch, it is preferable to set the temperature below the glass transition point and quench the material to make it substantially amorphous.

The stretching method may be either uniaxial stretching, sequential biaxial stretching or simultaneous biaxial stretching, but biaxial stretching is desirable because it is necessary to improve physical properties in both longitudinal and transverse directions for the purpose of use. In the present invention, the stretching ratio of the unstretched sheet is 1.5 in each of the longitudinal (longitudinal) direction and the lateral (width) direction.
In the present invention, the degree of plane orientation ^ΔP, which is 1.0 × 10 ⁻³ or less in a non-oriented sheet or film, can be obtained by appropriately selecting the stretching temperature in the range of 5 to 5 times and the stretching temperature in the range of 50 ° C. to 90 ° C. By increasing the amount to 3.0 × 10 ⁻³ or more, which is specified, a tough oriented film can be obtained even if it is thin.

ΔP represents the degree of orientation in the plane direction with respect to the thickness direction of the film, and is usually calculated by the following formula by measuring the refractive index in the directions of three orthogonal axes.

ΔP = {(γ + β) / 2} -α (α <β <γ) where γ and β are biaxial refractive indices orthogonal to the film surface, and α is a refractive index in the film thickness direction. Is.

ΔP depends on the crystallinity and the crystal orientation, but largely depends on the molecular orientation in the film plane. That is, an increase in ΔP leads to an increase in the molecular orientation in the plane of the film, particularly in the flow direction of the film and / or a direction orthogonal thereto, thereby increasing the strength of the film and improving the brittleness.

As a method for increasing ΔP, a molecular orientation method utilizing an electric field or a magnetic field can be adopted in addition to any known film stretching method.

The upper limit of ΔP is practically about 30 × 10 ^-3 , and if ΔP is made higher than this, there is a disadvantage that stretching becomes unstable or impossible.

By setting ΔP to be 3.0 × 10 ⁻³ or more as described above, the strength is remarkably improved, and the embrittlement caused mainly by spherulite growth, which is observed in the case of the non-oriented sheet, is reduced. Whitening can be prevented.

On the other hand, however, the thermal dimensional stability of the film becomes poor. Specifically, the film shrinks during the hot summer months. Alternatively, when the film is stored in a roll state, the film may be naturally contracted to cause slack or waviness in the film. Therefore, it is not suitable to be laminated with paper. Also, the film shrinks due to the heat applied during lamination,
There is a problem of curling.

Therefore, it is important that the polylactic acid-based film does not shrink, that is, it has thermal dimensional stability, in an atmosphere slightly higher than room temperature, that is, at a temperature of about 50 ° C. or higher.

Therefore, in a polylactic acid type film having a ΔP of 3.0 × 10 ⁻³ or more, the (ΔHm-ΔHc) of the film is 20 J / in order to obtain practical thermal dimensional stability.
g or more and {(ΔHm-ΔHc) / ΔHm} is 0.7
It is important to control to 5 or more.

That is, if these conditions are not satisfied,
The thermal dimensional stability of the film is poor, and problems such as shrinkage at a temperature applied by bonding, drying, aging, etc. are likely to occur, which is not practical. If the condition is exceeded, the thermal dimensional stability will be good, and there will be no practical problems.

ΔHm and ΔHc are obtained by differential scanning calorimetry (DSC) of a film sample, and
Hm is the amount of heat required to melt all the crystals when the temperature is raised at a heating rate of 10 ° C./minute, and is calculated from the area of the endothermic peak due to crystal melting that appears near the crystal melting point of the polymer. Further, ΔHc is obtained from the area of the exothermic peak generated during crystallization that occurs during the temperature rising process.

ΔHm mainly depends on the crystallinity of the polymer itself, and takes a large value for a polymer having high crystallinity. Incidentally, the complete homopolymer of L-lactic acid or D-lactic acid without a copolymer has a content of 60 J / g or more, and in the copolymer of these two kinds of lactic acid, ΔHm changes depending on the composition ratio. ΔHc is an index relating to the crystallinity of the film at that time with respect to the crystallinity of the polymer, and when ΔHc is large, the crystallization of the film proceeds in the temperature rising process. That is, it means that the crystallinity of the film was relatively low based on the crystallinity of the polymer. On the contrary, when ΔHc is small, it means that the crystallinity of the film was relatively high based on the crystallinity of the polymer.

1 for increasing (ΔHm-ΔHc)
One direction is to make a film with a relatively high degree of crystallinity from a polymer with a high crystallinity. The crystallinity of the film depends to a large extent on the composition of the polymer, and in order to make the ΔHm of the polymer itself to be 20 J / g or more, the composition ratio of L-lactic acid and D-lactic acid is 100: 0 to 94: 6. It is important to be within the range of 0 or within the range of 0: 100 to 6:94. Further, in order to reduce ΔHc, that is, in order to increase the crystallinity of the film, it is necessary to select the film processing conditions.

In order to increase the crystallinity of the film in the molding process step, especially in the biaxial stretching by the tenter method, it is useful to increase the stretching ratio to promote oriented crystallization, and to heat the film after stretching in an atmosphere having a crystallization temperature or higher. Is. It should be noted that the larger the ΔP, the lower the crystallization temperature tends to be, and in the case of the present invention, as a result of intensive studies, heat treatment is performed at least at 70 ° C. or higher, preferably 90 ° C. to 170 ° C. for 3 seconds or more. Can provide thermal dimensional stability. Within this range, the higher the heat treatment temperature and the longer the heat treatment time, the better the thermal dimensional stability.

The film thus obtained does not break or distort due to the tension and heat applied in the laminating process such as dry laminating, wet laminating, hot melt laminating, etc., and is extremely stable in laminate production. be able to. In addition, since the film is molecularly oriented and crystallized, spherulites do not grow even after a lapse of time, and therefore there is no whitening devitrification or embrittlement due to spherulites, and the appearance and mechanical properties and protective properties Maintains superior performance.

By stretching the polylactic acid-based polymer film so as to impart the characteristics within the above-specified range, the uniformity of the film thickness is enhanced, and the transparency and gloss are also improved. . Further, the impact resistance is also improved, and the same or higher effect can be obtained even with a thin film as compared with the case where a single piece of paper or an unstretched film is laminated.
The paper bonded to the oriented polylactic acid-based film is not particularly limited, and for example, printing paper, kraft paper, imitation paper, paperboard, etc. can be used. Further, a polylactic acid-based polymer film may be further attached to coated paper such as art paper and coated paper.

The above oriented polylactic acid-based film is attached to paper with an adhesive or a pressure-sensitive adhesive. As existing synthetic adhesives and adhesives, there are vinyl-based, acrylic-based, polyamide-based, polyester-based, rubber-based, urethane-based, etc., which are extremely thin and can be applied in small amounts and bonded together. Although the amount of the adhesive or the pressure-sensitive adhesive is small in the case of the laminate material, it is originally preferable that they are also biodegradable.For example, carbohydrates such as starch, proteins such as glue, gelatin, and casein, and unadded There are natural materials such as vulcanized natural rubber.

The constitution of the degradable laminate material of the present invention is as follows:
For example, a two-layer structure of oriented polylactic acid polymer film / paper,
There is a three-layered structure of oriented polylactic acid polymer film / paper / oriented polylactic acid polymer film, etc., but it is not particularly limited.

The degradable laminate material of the present invention is a bag,
It can be suitably used in the field of packaging materials such as boxes, trays, cups and lids. The paper can be partially punched out to form a “window”, and an oriented polylactic acid polymer film can be attached thereto to form a container for seeing through the contents. This transparent container for contents is suitable as a container with a window or a container in which the stored article can be easily confirmed from the outside. Furthermore, it is suitable for applications that require a beautiful appearance such as calendars, posters, book covers, etc .; display materials such as labels and stickers; packaging / packaging tapes; process paper used in the manufacture of various products. is there.

[0035]

EXAMPLES Examples of degradable laminate materials are shown below, but the present invention is not limited thereto. The measured values shown in the examples were measured and calculated under the following conditions.

(1) ΔP The refractive index (α, β,
γ) was measured and calculated by the following formula.

ΔP = {(γ + β) / 2} −α (α <β <γ) γ: maximum refractive index β in the film plane: refractive index in the in-plane direction orthogonal to the film α: in the film thickness direction Refractive index (2) ΔHm-ΔHc and (ΔHm-ΔHc) / ΔH
m Using DSC-7 manufactured by Perkin Elmer, based on JIS-K7122, the heat of crystal fusion ΔHm and the heat of crystallization ΔHc were obtained from the thermogram when the temperature was raised at a temperature increase rate of 10 ° C./min. , Calculated.

(3) Lamination Suitability An adhesive was evenly applied to a polylactic acid film cut into 100 mm × 100 mm and dried in an oven at 60 ° C. for 3 minutes to observe the shape change of the polylactic acid film. When the dimensional change is large, it is not suitable for pasting with paper.

(4) Heat resistance 100 mm × 100 mm laminate sample
The change after being left for 3 hours in a constant temperature bath at 0 ° C. was examined.

(5) Impact resistance Hydroshot high-speed impact tester HTM-1 type (Co., Ltd.)
The impact resistance was measured using Shimadzu Corporation). 100m
Paper, a film, and a laminate sample of these cut out to m × 100 mm were fixed with a clamp, a weight was dropped in the center of the film to give an impact, and the breaking energy when the sample was broken was read. The measurement temperature is 23 ° C., and the dropping speed is 3 m / sec. The lower the maximum load and energy when the film breaks, the poorer the impact resistance and the more brittle.

Example 1 The ratio of the structural unit composed of L-lactic acid to the structural unit composed of D-lactic acid was about 98: 2, the glass transition point was 58 ° C., the melting point was 175 ° C., and the weight average molecular weight was 18.
Thousands of polylactic acid in a 30mmφ single-screw extruder
It was extruded from a T die at 200 ° C. to prepare an unstretched sheet having a film thickness of 150 μm.

The above unstretched sheet is roll-stretched twice in the longitudinal direction, then stretched three-fold in the width direction with a tenter, and then heat-treated in the tenter at 100 ° C. for about 30 seconds to prepare an oriented polylactic acid-based film. did.

100 mm of the above oriented polylactic acid type film
Cut out to 100 mm, and use a polyurethane solvent adhesive (Takelac A-970 / Takenate A-19 = 15 /
1, manufactured by Takeda Pharmaceutical Co., Ltd.) was evenly applied to a thickness of 1 μm and dried in an oven at 60 ° C. for 3 minutes. At this time, there was no change in the appearance and dimensions of the film.

Next, a high-quality paper cut into the same size,
The oriented polylactic acid-based film was bonded with a roller under pressure, and aged at 40 ° C. for 24 hours to obtain a decomposed laminated material. Used fine paper (thickness 60μ
When the impact resistance of m and a mass of 51 g per 1 m ^{2 of} area) was examined by hydrate shot, the maximum load was 2 kgf and the breaking energy was 4 kgf · mm.

ΔP of the obtained oriented polylactic acid-based film,
(ΔHm-ΔHc), {(ΔHm-ΔHc) / ΔH
m}, and the suitability for laminating disassembled laminating materials,
The heat resistance and impact resistance are shown in Table 1. △ P, (△ Hm- △
Hc) and {(ΔHm-ΔHc) / ΔHm} are within the scope of the present invention.

(Example 2) Except that the conditions for producing an oriented polylactic acid based film from an unstretched sheet were as follows:
A decomposed laminated material was obtained in the same manner as in Example 1. Roll stretched 2.5 times in the longitudinal direction, then stretched 2.5 times in the width direction with a tenter, and subsequently 100 ° C in the tenter.
Heat treatment was performed for about 25 seconds to prepare an oriented polylactic acid-based film.

The properties of the obtained oriented polylactic acid-based film and the decomposed laminate material are shown in Table 1. △
P, (ΔHm-ΔHc), {(ΔHm-ΔHc) / ΔH
m} is the scope of the present invention.

Example 3 A polylactic acid having a structural unit consisting of L-lactic acid and a structural unit consisting of D-lactic acid in a ratio of about 96: 4, a glass transition point of 57 ° C., a melting point of 152 ° C. and a weight average molecular weight of 140,000 was used. Using the same apparatus as in Example 1,
It was extruded at 190 ° C. to prepare an unstretched sheet having a film thickness of 220 μm.

The unstretched sheet was roll-stretched 2.5 times in the longitudinal direction, and then stretched 3 times in the width direction with a temperature balance.
Subsequently, the product was heat-treated in a tenter at 120 ° C. for about 25 seconds to prepare an oriented polylactic acid-based film.

Using the above oriented polylactic acid-based film, a decomposition laminated material was prepared in the same manner as in Example 1. Table 1 shows the respective properties of the obtained oriented polylactic acid-based film and the decomposed laminate material. △ P, (△ Hm- △ H
c) and {(ΔHm-ΔHc) / ΔHm} are within the scope of the present invention.

Example 4 Polylactic acid having a ratio of structural units of L-lactic acid and structural units of D-lactic acid of about 95: 5, a glass transition point of 57 ° C., a melting point of 147 ° C. and a weight average molecular weight of 110,000 was used. Using the same apparatus as in Example 1,
It was extruded at 190 ° C. to prepare an unstretched sheet having a film thickness of about 250 μm.

The unstretched sheet was roll-stretched 1.5 times in the longitudinal direction, then stretched 1.5-fold in the width direction with a tenter, and then heat-treated in the tenter at 120 ° C. for about 40 seconds to obtain an oriented poly-sheet. A lactic acid-based film was created.

Using the above oriented polylactic acid-based film, a decomposition laminated material was prepared in the same manner as in Example 1. Table 1 shows the respective properties of the obtained oriented polylactic acid-based film and the decomposed laminate material. △ P, (△ Hm- △ H
c) and {(ΔHm-ΔHc) / ΔHm} are within the scope of the present invention.

(Comparative Example 1) Poly L-used in Example 1
Lactic acid in a 30 mmφ single-screw extruder at 200 ° C
It was extruded from a T-die by means of, and rapidly cooled with a casting roll, and pressed against paper with a nip roll. The thickness of the obtained polylactic acid sheet of the laminate was 100 μm. Table 1 shows the respective properties of the obtained oriented polylactic acid-based film and the decomposed laminate material.

(Comparative Example 2) The unstretched sheet used in Example 1 was roll-stretched by 1.2 times in the longitudinal direction, then stretched by 1.5 times in the width direction with a tenter, and subsequently 100 ° C in the tenter. Heat treatment was performed for about 30 seconds to prepare an oriented polylactic acid-based film.

Using the above oriented polylactic acid-based film, a decomposition laminated material was prepared in the same manner as in Example 1. Table 1 shows the respective properties of the obtained oriented polylactic acid-based film and the decomposed laminate material. Although (ΔHm-ΔHc) and {(ΔHm-ΔHc) / ΔHm} are within the range of the present invention, the plane orientation degree ΔP of the film is less than 3.0 × 10 ⁻³ , and It is outside the scope of the invention.

Comparative Example 3 An unstretched sheet having a film thickness of 310 μm was prepared in the same manner as in Example 1. The unstretched sheet was roll stretched twice in the longitudinal direction and then stretched three times in the width direction with a tenter to prepare an oriented polylactic acid-based film.

Using the above oriented polylactic acid-based film, a decomposition laminated material was prepared in the same manner as in Example 1. Table 1 shows the respective properties of the obtained oriented polylactic acid-based film and the decomposed laminate material. △ P and (△ Hm- △
Hc) is within the scope of this claim, but {(ΔHm-ΔH
c) / ΔHm} is less than 0.75, which is outside the scope of the present invention.

Comparative Example 4 Polylactic acid having a ratio of structural units of L-lactic acid and structural units of D-lactic acid of about 93: 7, a glass transition point of 57 ° C., a melting point of 125 ° C. and a weight average molecular weight of 110,000 was used. Using the same apparatus as in Example 1,
It was extruded at 180 ° C. to prepare an unstretched sheet having a film thickness of 170 μm. The unstretched sheet was roll-stretched 1.5 times in the longitudinal direction, then stretched 2 times in the width direction with a tenter, and subsequently heat-treated in the tenter at 80 ° C. for about 40 seconds to prepare an oriented polylactic acid-based film.

Using the above oriented polylactic acid type film, a decomposition laminated material was prepared in the same manner as in Example 1. Table 1 shows the respective properties of the obtained oriented polylactic acid-based film and the decomposed laminate material. ΔP and {(ΔHm-
ΔHc) / ΔHm} is within the scope of this claim, but
Hm-ΔHc) is less than 20 J / g, which is outside the scope of the present invention.

[0061]

[Table 1] Table 1 shows the comprehensive evaluation of the properties of the laminate material at the bottom. The evaluation is as follows.

⊚: Laminate material having particularly excellent properties ○: Laminate material having excellent properties Δ: Laminate material having practical level properties ×: Laminate material having practical level or lower properties Table 1 , ΔP, (ΔHm-ΔHc),
In Examples 1 to 4 in which {(ΔHm-ΔHc) / ΔHm} is within the range of the present invention, the laminate properties, heat resistance, and impact resistance are all within the range required as a laminate material, and the overall evaluation is ◎ to △. By laminating,
The impact resistance is larger than the maximum load of 2 kgf and the breaking energy of 4 kgf · mm of the used fine paper.

However, in Comparative Examples 1 to 4, various characteristics lack the range required for the laminate material, and the overall evaluation is x. That is, when a stretched oriented polylactic acid-based film within the scope of the present invention is used, an excellent degradable laminate material can be obtained.

[0064]

INDUSTRIAL APPLICABILITY As described above, the present invention is a container for see-through of contents, which uses a decomposable laminate material which does not make up for the defects of paper and has excellent properties as a composite material. It is possible to provide a container in which the contents are clearly visible without devitrification of the film even when the oriented polylactic acid-based film forming the object see-through part is exposed to high temperature during the laminating step.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B32B 27/36 B32B 27/36 C08G 63/06 ZBP C08G 63/06 ZBP // C08L 101/16 C08L 101 / 16 (72) Inventor Jun Takagi 5-8 Mitsuya-cho, Nagahama-shi, Shiga Mitsubishi Plastics Co., Ltd. Nagahama factory F-term (reference) 3E086 AC25 AD01 AD02 AD05 AD06 AD24 AD30 BA04 BA14 BA15 BB68 BB90 4F100 AK41A BA02 BA07 DC11B DG10B EJ37A GB16 JC00 YY00A 4J029 AA02 AB07 AC01 AC02 AD10 AE01 EA02 EA03 EA05 KB02 4J200 AA06 BA03 BA05 BA14 CA04 DA03 EA04

Claims (2)

[Claims] 1. A degree of plane orientation ΔP of 3.0 × 10 ⁻³ or more, and a heat of crystal fusion ΔH when the film is heated.
The difference (ΔHm-ΔHc) between m and the heat of crystallization ΔHc generated by crystallization during heating is 20 J / g or more and {(ΔHm
A container for seeing through contents, which is obtained by laminating an oriented polylactic acid-based film having a −ΔHc) / ΔHm} of 0.75 or more and a paper sheet partially punched to form a window. 2. An oriented polylactic acid-based film comprises L-lactic acid and D.
A copolymer having a ratio with lactic acid within the range of 100: 0 to 94: 6 or within the range of 0: 100 to 6:94.
A container for seeing through the described contents.